[Simh] DG Nova booting from another file or "device"?
Bruce Ray
Bruce at Wild-Hare.com
Wed Nov 18 02:42:13 EST 2015
G'day AJ -
Briefly...
The tape contains a disk/tape backup/restore utility that is somewhat
representative of those used with Point 4, and other 3rd-party DG
lookalike systems. It is a stand-alone utility that is bootable if it
exists as the first record of the first file of a mag tape or cartridge.
The usual procedure is to bootstrap the tape using the Nova APL function
(or just toggling in simple 2-instruction 'fat-finger' program). Once
the program is read into memory, it starts execution and displays its
introductory message. At this point another tape/cartridge may be
loaded onto the tape drive for backup or restore purposes.
I used our reNOVAte software for doing my investigations rather than
SimH due to convenience, and was able to run the program and exercise
its various functions. (Screen shots are attached.)
This particular utility is very specific regarding the type of disk
drive and IRIS logical units it supports.
The utility assumes two devices exist: a tape controller using device
code <022> and a disk controller using device code <027>. The tape
controller may or may not perform QIC to DG-style file handling
emulation since the original tape is not available to me.
The disk controller appears to use the standard DG "Zebra" controller
(Model 6060/6061/6067) programming model. However, it assumes a
non-standard disk geometry of 16 cylinders, 5 heads, and 32 sectors.
The tape file itself needs to be created in the SimH tape if it is to be
used with the default SimH tape driver. The QIC format may exist as a
single large data record of 16,384 bytes, or of multiple 512-byte
records followed by a file mark. (I can not tell its original format
given only the .bin file to work with.)
The utility also makes assumptions about tape read timing and CPU
instruction execution speed. Horrible programming technique, but
unfortunately not uncommon practice. Any such timing dependencies must
be found and compensated for in the device driver or instruction emulation.
Since there is no disk backup tape to load onto the disk, I used dummy
disk data for testing the disk-to-tape and tape-to-disk functions. Real
backup tape(s) would obviously be needed to restore the original system.
Bruce
On 11/14/2015 3:35 PM, Microtech Dart wrote:
> Thank you, Dell, and Sandy Strain, both of your responses were EXTREMELY
> helpful to me, and these all worked!
>
> Do either of you have any additional thoughts about how I could make
> what I believe to be a bootable file (extracted from a Microtech/Point4
> QIC tape) into a bootable device for the Nova?
>
> I'll start with the Minicom Disk To Tape Utility:
>
> http://microtechm1.blogspot.com/2015/09/minicom-disk-to-tape-copy-utility.html
>
> I've attached a .zip of the binary file that I extracted from this tape
> for reference. It's very small, so I zipped it up only so that the
> emailing process didn't interfere with or reject it.
>
> Thanks, all!
>
> -AJ
>
> On Sat, Nov 14, 2015 at 7:23 AM, Dell Setzer <dsetzer at panix.com
> <mailto:dsetzer at panix.com>> wrote:
>
> It's actually pretty easy. After booting RDOS, press ^E to return to
> the sim> prompt. Then, attach a host file to the MTA0 unit. If you
> give a host filename that doesn't yet exist, SIMH will create an
> empty tape file and attach it to MTA0:
>
> sim> attach mta0 testtape.tap
> MTA: creating new file
> sim>
>
> Then, give the simh G command to return to RDOS and init/f the MT0
> tape unit. Note that at the sim> prompt, the unit is called "MTA0"
> (or MTA1, MTA2, etc), while in RDOS the unit is called "MT0" (or
> MT1, MT2, etc):
>
> sim> g
> <presss return to get the RDOS prompt again>
> R
> init/f mt0
> CONFIRM? <press Y to confirm>
> R
>
> Now you can dump or copy files to the MT0 device:
> dump/v mt0:0 -.sr
> LITMACS.SR <http://LITMACS.SR>
> OSID.SR <http://OSID.SR>
> NSID.SR <http://NSID.SR>
> PARS.SR <http://PARS.SR>
> ALMSPD.SR <http://ALMSPD.SR>
> <etc.>
> R
> dump/v mt0:1 -.sv
> BURST.SV <http://BURST.SV>
> INITIALIZE.SV <http://INITIALIZE.SV>
> SEDIT.SV <http://SEDIT.SV>
> MACXR.SV <http://MACXR.SV>
> EDIT.SV <http://EDIT.SV>
> <etc.>
> R
> release mt0
> R
>
> After releaseing the tape, press ^E again to get to the sim> prompt
> and detach the tape file:
> ^E
> sim> detach mta0
> sim>
> Now you can inspect the testtape.tap tape image.
>
> Attaching an existing tape file is similar, except that at the RDOS
> prompt you'd do INIT rather than INIT/F:
>
> sim> attach mta0 testtape.tap
> sim> g
> R
> init mt0
> R
> load/n mt0:0
> LITMACS.SR <http://LITMACS.SR> 10/20/83
> OSID.SR <http://OSID.SR> 01/10/84
> NSID.SR <http://NSID.SR> 10/20/83
> PARS.SR <http://PARS.SR> 01/31/85
> <etc>
> R
> load/n mt0:1
> BURST.SV <http://BURST.SV> 05/09/85
> INITIALIZE.SV <http://INITIALIZE.SV> 05/02/85
> SEDIT.SV <http://SEDIT.SV> 05/02/85
> <etc>
> R
> release mt0
> R
>
> Hope this helps,
> ...dell
>
> On Sat, 14 Nov 2015, Microtech Dart wrote:
>
> Hi, I am completely new here, although I recognize the names of
> several who
> post here.
>
> I am trying to resurrect an extinct Microtech machine from 1982,
> which
> likely used the Point 4 processor, and the SimH DG Nova
> simulator *should*
> be compatible with the Point 4.
>
> I'm running the NOVA simulator now, with:
>
> NOVA simulator V4.0-0 Beta git commit id: 3be5125d
> sim> ATTACH DKP0 *rdos_d31.dsk*
> sim> set tti dasher
> sim> boot DKP0
>
> I'm teaching myself RDOS now with the
> RDOS_Command_Line_Interpreter Manual.
> <http://www.mirrorservice.org/sites/www.bitsavers.org/pdf/dg/software/rdos/093-000109-01_RDOS_Command_Line_Interpreter.pdf>
>
> Would anybody here be able to suggest some methods by which I could
> *create* a magnetic tape device on this SimH Nova simulator, and
> how I
> might write some files to that?
>
> I think that would be an excellent experiment for me to
> attempt. Then I
> can inspect the binary file in a hex editor, and see what it
> looks like,
> then compare to the binaries I've pulled off my Microtech/Point
> 4 tapes.
>
> --
>
> Thanks,
> -AJ
> http://MicrotechM1.blogspot.com
>
>
>
>
> --
>
> Thanks,
> -AJ
> http://MicrotechM1.blogspot.com
>
>
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